User management and permissions

　　1、Linux View all users in the

　　(1) In the terminal . Actually, just look at /etc/passwd Just a file .

　　(2) Look at the third parameter :500 The above , It's the user who built it later . Others are users of the system .

　　 Or use cat /etc/passwd |cut -f 1 -d :

　　2、 User management command

　　useradd notes ： Add users

　　adduser notes ： Add users

       userdel notes ： Delete account

　　passwd notes ： Set the password for the user

　　usermod notes ： Modify user command , Can pass usermod To modify the login name 、 User's home directory, etc ;

　　pwcov notes ： Synchronize users from /etc/passwd To /etc/shadow

　　pwck notes ：pwck Is to verify the user profile /etc/passwd and /etc/shadow Whether the content of the document is legal or complete ;

　　pwunconv notes ： yes pwcov The reverse operation of the system , It's from /etc/shadow and /etc/passwd establish /etc/passwd , It is then deleted /etc/shadow file ;

　　finger notes ： View user information tool

　　id notes ： Check the user's UID、GID And the user group to which they belong

　　chfn notes ： Change user information tool

　　su notes ： User switching tool

　　sudo notes ：sudo It's through another user to execute the command (execute a command as another user),su It's used to switch users , Then complete the corresponding task by switching to the user , but sudo It can execute commands directly from behind , such as sudo Unwanted root The password can be executed root The implementation of bestowal is only root To execute the corresponding command ; But it has to pass visudo To edit /etc/sudoers To achieve ;

　　visudo notes ：visodo It's the editor /etc/sudoers The order of ; You don't have to use this command , Direct use vi To edit /etc/sudoers The effect is the same ;

　　sudoedit notes ： and sudo It's almost functional ;

　　3、 Manage user groups (group) A tool or command of ;

　　groupadd notes ： Add user group ;

　　groupdel notes ： Delete user group ;

　　groupmod notes ： Modify user group information

　　groups notes ： Displays the user group to which the user belongs

　　grpck

　　grpconv notes ： adopt /etc/group and /etc/gshadow To synchronize or create /etc/gshadow , If /etc/gshadow Create if it does not exist ;

　　grpunconv notes ： adopt /etc/group and /etc/gshadow File content to synchronize or create /etc/group , Then delete gshadow file